The high energy cost in snowmaking is particularly attributed to the compressed air consumption in the air/water type snowmaking nozzles. A number of snowmaking devices involve motor driven fans which use little or no compressed air. The initial cost of this equipment is generally high and must be amortized over a long period even though operational costs are lower than the air/water methods which have low initial investment cost. Many improvements have been made since snowmaking's first applications.
U.S. Pat. No. 4,480,788 to Michael Manhart, issued Nov. 6, 1984, discloses a nozzle in which an adequate air water mixture is proposed by a plurality of bores for initial mixing and a restriction of the same area within. This air and water mixture is then discharged through a second set of orifices.
U.S. Pat. No. 4,465,230 to Robert M. Ash, issued Aug. 4, 1984, is representative of an air and water type nozzle in which water is ejected through a series of orifices and thence through columns of compressed air at the final orifices surrounding the water as it is projected into ambient air.
U.S. Pat. No. 3,923,247 to Jeffery White, issued Dec. 2, 1975, describes a mixing chamber for air and water which is discharged through a defined annular gap including a specially designed converging and diverging horn to accelerate the air water mixture in two stages.
U.S. Pat. No. 3,923,246 to Oscar F. Cloutier, issued Dec. 2, 1975, gives consideration to a spiraling column of air through a single mixing chamber to thoroughly mix the air and water.
U.S. Pat. No. 3,838,815 to Bruce A. Rice, issued Oct. 1, 1974, is constructed with a series of fixed annular opening approximately 0.01 to 0.03 inches across which are fine enough so that water breaks down into fine droplets carried along by the air stream.
U.S. Pat. No. 3,716,190 to James A. Lindlof, issued Feb. 13, 1973, incorporates a Venturi section to first mix air and water and finally a swirl chamber at the final discharge area utilizing an expanding stream of minute air bubbles to atomize the water.
It is, therefore, apparent that much attention has been given to the atomization of the water by mixing it with compressed air. In an overview of the market, it might be noted that snowmaking nozzles with a multitude of small diameter orifices, in general, tend to perform more efficiently at marginally freezing temperatures than those with a larger single orifice. Whereas, at colder temperatures those with smaller multi-orifices often suffer from insufficient water flow as compared to the larger, single orifice nozzles. It may also be said that most air/water snowmaking devices tend to operate most efficiently in a rather narrow range of their total effective capacity.